Surfactants not toxic to bacteria

Abstract

An oilfield treatment method is given that uses fluids that contain surfactants used as foamers and/or viscosifiers such that the fluids pass the Alberta Energy and Utilities Board Directive 27 requirements for low toxicity to certain bioluminescent bacteria. Such fluids may be used in oilfield treatments, for example drilling and stimulation, near fresh water aquifers. The surfactants are certain non-ionic surfactants that are not aromatic, or certain amphoteric surfactants (that can be neutral), or certain zwitterionic surfactants, (in which both positive and negative charges are present in a single molecule so that the whole molecule is neutral).

1. An oilfield treatment method, comprising:
 providing a slickwater treatment fluid comprising a polymer-based friction-reducer and a betaine zwitterionic surfactant that allows the slickwater treatment fluid to pass the toxicity test according to the Alberta Energy and Utilities Board Guide G50, 1996, (Directive 050) for Drilling Waste Management wherein said betaine comprises erucylamidopropyl betaine or cocoamidopropyl betaine, wherein the concentration of the active component of the surfactant in the fluid is from about 0.004 to about 2.4 weight %; and 
 injecting the slickwater treatment fluid down a well. 
 
     
     
       2. The method of  claim 1  further comprising generating a foam from said fluid. 
     
     
       3. The method of  claim 2  wherein the concentration of the active component of the surfactant in the liquid phase of the foam is from about 0.004 to about 2.4 weight %. 
     
     
       4. The method of  claim 3  wherein the concentration of the active component of the surfactant in the liquid phase of the foam is from about 0.008 to about 1 weight %. 
     
     
       5. The method of  claim 1  wherein the surfactant is in a concentration sufficient to impart additional viscosity to the fluid. 
     
     
       6. The method of  claim 1  wherein the surfactant is in a concentration sufficient to impart viscoelasticity to the fluid. 
     
     
       7. The method of  claim 1  wherein the treatment fluid comprises a viscosifying amount of a water soluble polymer. 
     
     
       8. The method of  claim 1  wherein the fluid further comprises a foam stabilizer. 
     
     
       9. The method of  claim 1  wherein said fluid further comprises a co-surfactant. 
     
     
       10. The method of  claim 1  wherein the treatment fluid comprises a rheology enhancer. 
     
     
       11. The method of  claim 1  wherein the treatment fluid comprises an acid selected from the group consisting of hydrochloric acid, hydrofluoric acid, formic acid, acetic acid, polylactic acid, polyglycolic acid, lactic acid, glycolic acid, sulfamic acid, malic acid, citric acid, tartaric acid, maleic acid, methylsulfamic acid, chloroacetic acid, and mixtures thereof. 
     
     
       12. The method of  claim 1  wherein the fluid further comprises a breaker for the surfactant. 
     
     
       13. The method of  claim 1  wherein the concentration of the active component of the surfactant in the fluid is from about 0.008 to about 1 weight %. 
     
     
       14. The method of  claim 1  wherein the fluid is energized.